Air inlet means for self-cleaning oven



Dec. 19, 1967 R. D. CH|SHOLM AIR INLET MEANS FOR SELF-CLEANING OVEN Filed March 21, 1966 INVENTOR ROY D, Cl-HSHOLM Wm HIS ATTORMEY I i r tates 3,358,674 AIR INLET MEANS FOR SELF-CLEANlNG OVEN Roy 1). Chisholm, Louisville, Ky., assignor to General Electric Company, a corporation of New York Filed Mar. 21, 1966, Ser. No. 535,882 7 Claims. (Cl. 126-193) ABSTRACT OF THE DISCLOSURE The present invention relates to domestic baking ovens and particularly to an automatic self-cleaning oven with an air inlet means for regulating the entry of room air into the oven cavity during a high temperature self-cleaning cycle.

Ovens are commercially available which incorporate an automatic, self-cleaning cycle using the principle of pyrolysis for removing food soil and grease spatter from the inner wall surfaces of the oven liner. Such cleaning cycles decompose all the food soil and grease spatter lodged on the oven walls by degrading the soil into gaseous products which are then passed through an oxidation unit or catalytic smoke eliminator to further degrade the gases before they are returned to the ambient kitchen atmosphere.

For optimum operation of the oxidation unit, it is necessary to supply a small amount of oxygen in the form of room air into the oven cavity. It is possible to provide an air inlet means by creating an opening in the door gasket adjacent the lower edge of the oven door so as to form a gap between the door and the oven body. However, the amount of air that is allowed to enter the oven cavity is critical to the optimum operation of the oxidation unit. Therefore, manufacturing tolerances would have to be held very close in order to insure optimum operation of the oxidation unit. The best approach is to design the air inlet means within the oven door.

The principal object of the present invention is to provide an improved means for regulating the entry of air into an oven.

A further object of the present invention is to provide an improved air passage through a portion of the door of a self-cleaning oven.

A further object of the present invention is to provide such an improved air passage which is easily constructed from a minimum number of inexpensive parts and is reliable in operation.

The present invention, inaccordance with one form thereof, is embodied in a domestic oven having an oven liner and an access door forming an oven baking cavity. The door is pivoted for movement between a door open and a door closed position and includes an inner door liner which extends across the oven cavity and is slightly spaced from the oven liner when the door is in its closed position. Door sealing means are provided and adapted to seal the space between the inner door liner and the oven liner when the door is in its closed position. In order to provide for a regulated supply of air to the oven cavity a portion of the door liner adjacent the sealing means is formed as a pair of spaced walls which provide a passage bypassing the sealing means. At least one opening of predetermined size is formed in the door liner on each side ate nt 3,358,674 Patented Dec. 19, 1967 of the sealing means to allow a regulated amount of air to enter the oven cavity when the door is in its closed position.

My invention will be better understood from the following description taken in conjunction with the accompanying drawings and its scope will be pointed out in the appended claims.

FIGURE 1 is a partial right side elevational view of an electric oven illustrated as a built-in wall oven with some parts broken away and some in cross-section for purposes of illustration.

FIGURE 2 is a fragmentary cross-sectional elevational view on an enlarged scale showing the interrelation of the lower portion of the oven door with the front of the oven body.

FIGURE 3 is a fragmentary elevational view of the inner surface of the lower edge of the door of FIGURE 1 illustrating details of the sealing means.

Considering now the drawings, and in particular FIG- URE 1, there is shown a built-in wall oven body 10 with some side panels broken away and some in cross-section to show an oven cooking cavity 11. The cavity 11 is formed by a box-like oven liner 12 with a front opening that is adapted to be closed by an oven door 13 that is shown hinged on a lower horizontal axis. The particular oven shown is an electric oven, but the present invention is also adaptable for use in a gas heated oven. As is conventional in this art there is a lower baking element 15 and an upper broiling element 16 for use during normal cooking operations that range in temperature from about F. to about 550 F. Additional heating means is used in the form of a perimeter or mullion heater 17 adjacent the front of the oven liner 12 and encircling the innermost portion of the oven door so as to obtain generally uniform wall temperature within the oven cavity during the heat cleaning cycle. It will be noted that the mullion heater is protectively enclosed behind a front flange 18 of the oven liner 12. Due to the high temperatures encountered in this oven, an extra amount or thickness of thermal insulation 19 such as fiberglass or the like is assembled around the outside of the oven liner 12 for retaining as much as possible of the oven heat present within the oven cavity.

The basic construction of the door 13 comprises three sheet metal panels that are best seen in FIGURE 2; namely, an outer door panel 25, an inner door liner 26, and a floating inner panel 27. The basic structure of one such door is fully described and claimed in Patent 3,189,020, issued to Clarence Getman on June 15, 1965, and assigned to the General Electric Company, assignee of the present invention.

The outer door panel 2 5 is of a shallow pan-shape by virtue of the fact that it has a small, rearwardly-turned peripheral flange 29. The inner door liner 26 is also generally pan-shaped, including a generally planar surface or portion 30 adapted to fit substantially across the opening of the oven cavity and a first forwardly-turned peripheral flange 31 adapted to extend outwardly from the front opening in the oven cavity as seen in FIGURE 2. The peripheral edge of the door liner 26 is further provided with an L-shaped portion 32 extending from the flange 31 and telescoping within the flange 29 of outer door panel 25. The floating inner panel 27 is also of a pan-shaped construction with a front-turned flange 33 which is held to the inner door liner 26 to sandwich a woven glass fiber gasket 34 therebetween. Suitable clamps may be used to hold the gasket firmly in place. The space defined by the outer door panel 25, inner door liner 25 and the floating inner panel 27 is filled with a suitable insulation material 35. The oven door 13 is provided with a door handle 36 which is held in place with suitable fastening means such as screws (not shown) that extend from the inner side of the door into the handle to serve as the principal means of holding the inner outer door panel 25 and the door liner Z6 firmly together.

-T he gasket 34 is adapted to bear against the front flange 18 of the oven liner 12 as is best seen in FIGURE 1 so as to seal around the major portion of the periphery of the door. As can be best seen in FIGURE 3 however, the gasket 34 is discontinuous along a portion of the lower edge of the inner door liner 26 so that a gap would be present in this area were it not for a flexible strip of material 37 which is attached to the flange 31 of the inner door liner 26. The strip of material 37 depends from the flange 31 as seen in FIGURE 2 and bears against a front edge of a breaker frame 38.

The front flange 18 of the oven liner 1?; bears against the breaker frame 38 and holds the breaker frame in place while the breaker frame functions to thermally isolate the oven liner 12 from the oven body It In the oven construction shown in the drawings, the circuit and temperature control components illustrated generally as element 40, are located in a front control panel 41 positioned directly above the oven door 13. Such components might include an oven selector switch, a clock timer, oven thermostat for controlling both the normal cooking operation as well as the hightemperature, heat-cleaning cycle. Of course, the heating circuit would include the necessary electrical interlock and door locking means illustrated only as handle member 42 but designed to insure that the heat-cleaning cycle cannot raise the temperature above the normal cooking temperature range unless the oven door is both closed and locked. Moreover, the oven door may not be unlocked while the oven temperature is above about 600 F.

Oven cavity 11 is also provided with an oven vent 43 in the top wall of the oven liner 12 for exhausting the hot oven gases from the oven cavity 11. Interposed in the oven vent 43 is a catalytic oxidation unit 44 which is a small, separately heated chamber that includes a catalytic surface (not shown) to further decompose the smoke, odor, and gases pouring therethrough before they are returned to the kitchen atmosphere. Leading from the oxidation unit is an additional duct 45 that directs the gases to the front of the atmosphere. This oxidation unit 44 may be of the general type described and claimed in the patent of Stanley B. Welch No. 2,900,483 which is assigned to the General Electric Company, assignee of the present invention, and it is not shown in greater detail because it does not form part of the present invention.

As was mentioned previously, it is necessary to provide a supply of oxygen for the combustion of the exhaust gases within the oxidation unit. This oxygen is supplied by creating a gentle sweep of room air through the oven cavity. The oven is designed for this air to enter the oven cavity through an air inlet means or passage 50 best illustrated in FIGURE 2 built into the lower portion ot the door liner 26. Passage 50 is formed by cooperation of the generally planar surface 30 and flange 31 of door liner 26 with an insulation guard in the form of an additional Z-shaped member 51 provided within the door liner 25. The additional member 51 is spaced from both the inner surface 30 and flange 31 to form the passage which bypasses the oven sealing means provided by the gasket 34 and flexible strip of material 37.

Openings of predetermined individual and total size, such as the one illustrated at 52, are provided in the flange 31, between the flexible strip of material 37 and the L-shaped portion 32. Similar openings, such as that illustrated at 53, are provided in the planar surface 30 on the other side of flexible strip 37. Thus, the passage 56 is formed so that a regulated amount of air may bypass the sealing means and enter the oven cavity. This air flow is illustrated by appropriate arrows in FIGURE 2. While only one opening 52 in flange 31 and one opening 53 in planar surface 30 are illustrated, it will be oven for discharge into the understood that a number of openings could be provided in each member so long as the number of openings and their size are such as to allow a properly regulated amount of air to enter the oven cavity.

The length and shape of the path for the air as well as the size of the openings 52 and 53 and the size of the passage 50 not only regulate the amount of air which enters the oven cavity 11, but also serve to prevent any flame which might result from excessive grease on the liner during a heat cleaning cycle from flashing back through the passage to the outside of the oven.

The purpose of additional member 51 is to insure that the insulation 37 does not block passage St). If the particular insulation material used is sufliciently self-supporting all or part of the additional member 51 should be omitted. For instance the use of a slab of potassium titrate would allow complete omission of the member 51. In that case the passage 50 would be formed merely by spacing the lower, inner portion of the insulation slab from planar surface 30 and flange 31 of door liner 26.

Modifications of this invention will occur to those skilled in the art, therefore, it is to be understood that this invention is not limited to the particular embodiments discussed, but that it is intended to cover all modifications which are within the true spirit and scope of this invention as claimed.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A door construction for a domestic oven having an insulated oven cavity formed by a box-like oven liner with an access opening formed in one end thereof; said door including an outer panel and an inner door liner joined to said panel to form a space therebetween, said space being substantially filled with thermal insulation; said door being mounted for pivotal movement between a door open and a door closed position; said door liner extending across the opening of the cavity and being slightly spaced from the oven liner when said door is in its closed position; a strip of thermal gasket material attached to said door to seal the space between the oven liner and said door liner; said strip being discontinuous along a portion of the lower side of said door liner closest to the pivotal mount of said door; a flexible strip of material extending along said portion of said door liner and adapted substantially to complete the seal between said door and oven liner; said portion of said door liner being spaced from the insulation to provide a passage bypassing said flexible strip of material; and a plate member assembled within the inner door liner along the lower edge of the door structure to form an air inlet duct therewith, said duct having a first narrow elongated opening in the lower portion of the inner door liner outside the strip of thermal gasket material and a second narrow elongated opening in the inner door liner in the space where the strip of thermal gasket material is discontinuous whereby substantially all air entering the oven cavity is metered through the said air inlet duct.

2. A door construction for a domestic oven having an insulated oven cavity formed by a box-like oven liner with an access opening formed in one end thereof; said door including an outer panel and a door liner joined to said panel to form a space therebetween, said space being substantially filled with insulation; said door being mounted for pivotal movement between a door open and a door closed position; said door liner extending across the opening of the cavity and being slightly spaced from the oven liner when said door is in its closed position; a strip of thermal gasket material attached to said door and extending beyond said door liner to seal the space between the oven liner and said door liner; said strip being discontinuous along a portion of the side of said door liner closest to the pivotal mount of said door; a flexible strip of material extending along said portion of said door liner and adapted substantially to complete the seal between said door and the oven liner; and an insulation guard assembled in the inner door liner along the lower edge of the door structure to form an air inlet duct therewith, said duct having a first narrow elongated opening in the lower portion of the inner door liner outside the said strip of gasket material, and a second narrow elongated opening in the inner door liner in the area of the spaced apart ends of the gasket strip, whereby substantially all air entering the oven cavity is metered through the said air inlet duct.

3. A door construction for a domestic oven having an insulated oven cavity formed by a box-like oven liner having an access opening in one end thereof; said door including an outer panel and an inner door liner joined to said panel to form a space therebetween, said space being substantially filled with insulation; said door being mounted for pivotal movement between a door open and a door closed position; said inner door liner including a generally planar surface adapted to extend substantially across the access opening and a flange adapted to extend outwardly adjacent and slightly spaced from the peripheral edge of the oven liner opening when said door is in its closed position; a strip of thermal gasket material attached to said door and extending beyond said door liner to seal the space between the oven liner and said door liner; said strip being discontinuous along a portion of the side of said door liner closest to the pivotal mount of said door; a fiexible strip of material extending along said portion of said door liner and adapted substantially to complete the seal between said door and the oven liner; and an insulation guard assembled in the inner door liner along the lower edge of the door structure to form an air inlet duct therewith, said duct having a first narrow elongated opening in the lower portion of the inner door liner outside the said strip of gasket material, and a second narrow elongated opening in the inner door liner in the area between the spaced apart ends of the gasket strip whereby substantially all air entering the oven cavity is metered through the said air inlet duct.

4. A door construction for a high temperature domestic oven having an insulated oven cavity formed by a box-like oven liner and a front-opening access door, said door having an outer door panel, an inner door liner, and an inner panel fastened over the inner door liner, thermal insulation interposed between the outer door panel and the inner door liner as well as between the door liner and inner panel, a strip of thermal gasket material sandwiched between the peripheral edge of the inner panel and the door liner and extending beyond the confines of the inner panel to serve as a door gasket that is adapted to seat against the mouth of the oven liner; the invention comprising an insulation guard assembled in the inner door liner along the lower edge of the door structure to form an air inlet duct therewith, said inlet duct having a first narrow elongated opening in the lower portion of the inner door liner outside the said door gasket and a second narrow elongated opening in the gasket support section of the liner which is adapted to communicate with the oven cavity, and a second gasket member located in the door gap area beneath the said second narrow elongated opening in the inner door liner to require that substantially all air entering the oven cavity is metered through the said air inlet duct.

5. A door construction as recited in claim 4 wherein the strip of gasket material has two opposite ends which are spaced apart along the bottom portion of the door, the said second narrow elongated opening being located in the gasket support section between the two spaced ends of the strip of gasket material.

6. A door construction as recited in claim 5 where the said insulation guard follows substantially the contour of the inner door liner to form a thin air inlet duct.

7. A door construction for a high temperature oven having an insulated oven cavity formed by a box-like oven liner and a front-opening access door, said door comprising an outer door panel and an inner door liner, thermal insulation interposed between the said panel and liner, a strip of thermal gasket material mounted between the inner door liner and the front of the oven liner when the door is in a closed position, the said strip of gasket material having two opposite ends which are spaced apart along the bottom portion of the door, and an insulation guard assembled in the inner door liner along the bottom edge of the door structure to form an air inlet duct therewith, said duct having a first narrow elongated opening in the lower portion of the inner door liner outside the said strip of gasket material and a second narrow elongated opening in the inner door liner in the space between the spaced apart ends of the gasket strip, and a second gasket member mounted between the inner door liner and the front of the oven liner in the area beneath the said second narrow elongated opening and generally extending for a length spanning the distance between the spaced ends of the gasket strip so that substantially all air entering the oven cavity is metered through the said air inlet duct.

UNITED STATES PATENTS 2,965,095 12/1960 Pearce et a1. 126-2l 3,063,441 11/1962 Stoligrosz l2621 KENNETH W. SPRAGUE, Primary Examiner. 

1. A DOOR CONSTRUCTION FOR A DOMESTIC OVEN HAVING AN INSULATED OVEN CAVITY FORMED BY A BOX-LIKE OVEN LINER WITH AN ACCESS OPENING FORMED IN ONE END THEREOF; SAID DOOR INCLUDING AN OUTER PANEL AND AN INNER DOOR LINER JOINED TO SAID PANEL TO FORM A SPACE THEREBETWEN, SAID SPACE BEING SUBSTANTIALLY FILLED WITH THERMAL INSULATION; SAID DOOR BEING MOUNTED FOR PIVOTAL MOVEMENT BETWEEN A DOOR OPEN AND A DOOR CLOSED POSITION; SAID DOOR LINER EXTENDING ACROSS THE OPENING OF THE CAVITY AND BEING SLIGHTLY SPACED FROM THE OVEN LINER WHEN SAID DOOR IS IN ITS CLOSED POSITION; A STRIP OF THERMAL GASKET MATERIAL ATTACHED TO SAID DOOR TO SEAL THE SPACE BETWEEN THE OVEN LINER AND SAID DOOR LINER; SAID STRIP BEING DISCONTINUOUS ALONG A PORTION OF THE LOWER SIDE OF SAID DOOR LINER CLOSEST TO THE PIVOTAL MOUNT OF SAID DOOR; A FLEXIBLE STRIP OF MATERIAL EXTENDING ALONG SAID PORTION OF SAID DOOR LINER AND ADAPTED SUBSTANTIALLY TO COMPLETE THE SEAL BETWEEN SAID DOOR AND OVEN LINER; SAID PORTION OF SAID DOOR LINER BEING SPACED FROM THE INSULATION TO PROVIDE A PASSAGE BYPASSING SAID FLEXIBLE STRIP OF MATERIAL; AND A PLATE MEMBER ASSEMBLED WITHIN THE INNER DOOR LINER ALONG THE LOWER EDGE OF THE DOOR STRUCTURE TO FORM AN AIR INLET DUCT THEREWITH, SAID DUCT HAVING A FIRST NARROW ELONGATED OPENING IN THE LOWER PORTION OF THE INNER DOOR LINER OUTSIDE THE STRIP OF THERMAL GASKET MATERIAL AND A SECOND NARROW ELONGATED OPENING IN THE INNER DOOR LINER IN THE SPACE WHERE THE STRIP OF THERMAL GASKET MATERIAL IS DISCONTINUOUS WHEREBY SUBSTANTIALLY ALL AIR ENTERING THE OVEN CAVITY IS METERED THROUGH THE SAID AIR INLET DUCT. 